石油与天然气地质 ›› 2020, Vol. 41 ›› Issue (5): 903-912, 984.doi: 10.11743/ogg20200502

• 油气地质 • 上一篇    下一篇

渤海湾盆地渤中19-6凝析气田天然气成因及油气成因关系判识

胡安文(), 王德英, 于海波, 江涛, 孙哲   

  1. 中海石油(中国)有限公司 天津分公司 渤海石油研究院, 天津 300459
  • 收稿日期:2020-03-23 出版日期:2020-10-28 发布日期:2020-10-22
  • 作者简介:胡安文(1989-),男,工程师,油气地球化学与石油地质。E-mail:827578022@qq.com
  • 基金资助:
    国家科技重大专项(2016ZX05024-003)

Genesis of natural gas and genetic relationship between the gas and associated condensate in Bozhong 19-6 gas condensate field, Bohai Bay Basin

Anwen Hu(), Deying Wang, Haibo Yu, Tao Jiang, Zhe Sun   

  1. Bohai Petroleum Research Institute, Tianjin Branch of CNOOC, Tianjin 300459, China
  • Received:2020-03-23 Online:2020-10-28 Published:2020-10-22

摘要:

综合运用油气地球化学分析方法,分析了渤海湾盆地渤中19-6凝析气田天然气成因,并对凝析油与天然气的成因关系进行了判识。研究结果表明,渤中19-6凝析气田天然气为以烃类气为主的湿气,C1/(C2+C3)值偏低,介于6.4~7.3,甲烷碳同位素值集中分布于-38.0‰~-39.0‰,乙烷碳同位素偏重,介于-25.4‰~-27.0‰,为偏腐殖型干酪根裂解气,与沙河街组三段烃源岩具有可比性,源自沙河街组三段烃源岩。多项凝析油和天然气成熟度判别参数表明,渤中19-6凝析气田凝析油和天然气主要处于成熟阶段,但天然气成熟度略高于凝析油。多项地质证据表明,渤中19-6凝析气田经历了“早油晚气”的油气成藏过程,凝析油主成藏期(12 Ma以来)早于天然气(5 Ma以来)。

关键词: 成熟度, 气-源对比, 凝析油, 天然气, 渤中19-6凝析气田, 渤海湾盆地

Abstract:

The genesis of natural gas in the Bozhong 19-6 gas condensate field in the Bohai Bay Basin is analyzed by means of petroleum geochemical analyses, and the genetic relationship between condensate and natural gas is thereby determined.The results show that the natural gas in the Bozhong 19-6 gas condensate field is mainly composed of wet hydrocarbon gases with relatively low C1/(C2+C3) values ranging from 6.4 to 7.3, and carbon isotope values of methane and ethane ranging from -38.0‰ to -39.0‰ and from -25.4‰ to -27.0‰, respectively, indicating humic-prone kerogene-cracked gases probably derived from the source rocks of the third member of the Shahejie Formation.A number of condensate and gas maturity parameters show that both condensate and natural gas from the field are mature, with natural gas slightly maturer than condensate.Geological evidences also reveal that the field went through a hydrocarbon accumulation process of "early oil and late gas", with the main condensate accumulation stages (since 12 Ma) prior to those of natural gas (since 5 Ma).

Key words: maturity, gas-source correlation, condensate, natural gas, Bozhong 19-6 gas condensate field, Bohai Bay Basin

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